WTF is the speed of gravity

[Phil_de_geezer]

Ned, i'm confused. Are you saying that the article infers the points you made or are you stating them as fact?

[Lefty Scaevola]

Re: Re: Re: WTF is the speed of gravity

Originally posted by Lefty Scaevola
Do they theorize it alwys to be the speed of light in a vaccum, or is it suposed to be slowed passing through other media as light is so slowed?

Anybody got an answer for this yet?

[IoT]

Gravity itself is not matter. It is a force that arises from the interaction of objects with "gravitaional" mass. It is postulated that virtual gravitons are the propagator of this force in a similar way that virtual photons are the propagator for the electro-weak force. (Using the particle model of gravity rather than Eiensteins essentiall geometric model). Further the graviton itself is posulated to be a zero charge, zero rest mass spin 2 particle meaning that:

a) It travels at the speed of light.

b) It is a Boson (integer spin). This means, amongst other things that gravitons are completely indistinguishable from one another. If were were able to mix 2 together in a box, afterwards you would not be able tell which one was which.

Grand Unified Theories (GUTs) arise from the belief that the 4 fundamental forces of nature; Strong, Weak, Electromagnetic and Gravitational, are all facets of the same underlying single force.

[Phil_de_geezer]

Do they theorize it alwys to be the speed of light in a vaccum, or is it suposed to be slowed passing through other media as light is so slowed?

AFAIK, no substance has been discovered that affects gravity in this way. It would present... odd anomalies for physics.

[IoT]

Re: Re: Re: Re: WTF is the speed of gravity

Originally posted by Lefty Scaevola


Anybody got an answer for this yet?

I am not certain but I imagine that intervening mass wouldd at a minimum cause dispersal of gravity waves. And thinking about it a bit more it's possible that the vacuum itself would cause some shielding. There is no such thing as a pure vacuum - its more a seething foam. Short lived virtual particle-antiparticle pairs are being created all the time and these particle/anti-particle pairs have mass.

[Phil_de_geezer]

Am i right in thinking that exchange bosons are supposed to work by changing the momentum of the parent particle when they are emitted?

[IoT]

Originally posted by Phil_de_geezer
Am i right in thinking that exchange bosons are supposed to work by changing the momentum of the parent particle when they are emitted?

That's my understanding. Essentiall momentum has to be conserved and emitting an exchange particle requires an appropriate change in the emitter and ultimately in the absorber too. This is a very simplified view of what happens and its been many years since my undergrad particle physicis courses. You can bet there is a ton of Quantum Mechanics in there somewhere

[Phil_de_geezer]

Thanks for replying so quickly!

If what i said about exchange bosons was corect then there is something that puzzles me. Gravity seems to work backwards when u consider the momentum chages that take place when the boson is emitted and when it collides.

[IoT]

A quick search on Google (to refresh my memory honest )

http://home.fnal.gov/~bugel/fineman.html

Essentially exchange bosons, which are always virtual, can have positve or negative momentum.

[Lefty Scaevola]

Re: Re: Re: Re: Re: WTF is the speed of gravity

Originally posted by IoT


There is no such thing as a pure vacuum - its more a seething foam. Short lived virtual particle-antiparticle pairs are being created all the time and these particle/anti-particle pairs have mass.

Not to metion dark matter wich emit gravity and dark ernergy which appear to emit anti gravity.

[Ned]

Originally posted by Phil_de_geezer
Ned, i'm confused. Are you saying that the article infers the points you made or are you stating them as fact?

The article states the facts and concludes that they are consistent with Lorentzian Relativity and inconsistent with Special Reltivity.

But these are the conclusions of the author who issues a challenge to the adherents of Special Relativity to provide an explanation.

The universe is consistent with Lorentzian Relativity, not Special Relativity. Special Relativity (Einstein) says than nothing can propagate faster than the speed of light. Lorentzion Relativity does not.

Gravity clearly propagates much faster. It is also possible to travel faster than the speed of light in the Lorentzian universe.

[Phil_de_geezer]

Dark matter is only 'dark' cos we can't see it, that is to say that it doesn't emit radio or electromagntic waves.

Why is gravity so "obviously" propagating faster than the speed of light?

[IoT]

And more accurately Eiensteinian relativity forbids anything crossing the speed of light barrier. It does not a priori forbid the existance of particles that travel faster than the speed of light - they just cannot be slowed to below the speed of light. Hence the proposal of tachyons - although how you would prove thier existance is beyond me.

[Ethelred]

Originally posted by SlowwHand
http://www.ldolphin.org/vanFlandern/gravityspeed.html

Crank site.

Even though he has a real science education he is still a crank.

Lambert Dolphin is under the delusion that the Earth is only about 6000 years old. So to patch physics he and others sometimes pretend real hard that the speed of light is EXTREMELY variable. Carefully ignoring the fact that it would cause other variable to change so much the Earth would be a molten ball with metalic vapor for an atomosphere due the accelerated decay of radioactive material that he needs to make the Earth look so young.

[KrazyHorse]

Re: Re: Re: WTF is the speed of gravity

Originally posted by Lefty Scaevola


Do they theorize it alwys to be the speed of light in a vaccum, or is it suposed to be slowed passing through other media as light is so slowed?

Virtual particles are not "slowed" as real ones are (real ones aren't slowed either; just that the path they take isn't quite an uninterrupted straight line).

The speed of light in a material is not even a constant over all frequencies. That's why prisms split the spectrum...